In machine tools of the type provided with a base member, a worktable fixedly or movably mounted on the base member and a gantry also fixedly or movably mounted on the base member, there usually is provided a toolhead assembly mounted on the gantry. Such machines further are typically provided with servo motors operated by a programmable computer for displacing the worktable or gantry longitudinally relative to the base member or along an x-axis, displacing the toolhead assembly transversely relative to the base member or along a y-axis and displacing a tool carrying spindle assembly usually along a vertical line of travel or along a z-axis to perform various work functions on one or more work pieces loaded onto the worktable.
To increase the flexibility and possibly the productivity of such machines, it has been the practice in the prior art to provide multiple tool availability. This has been accomplished primarily by providing multiple toolhead assemblies, turret type toolhead assemblies or tool changer assemblies on such machines. Providing multiple toolhead assemblies is a costly arrangement, requiring multiple drive motors, frequency converters and spindles. Turret type toolhead assemblies and tool changer assemblies also are costly to produce. It thus has been found to be desirable to provide a toolhead assembly having multiple tool availability which is effective in performance in providing greater flexibility of the machine and increased productivity yet comparatively economical to manufacture.